Compressor valve structure



Oct. 13, 1959 Filed Sept. 4, 1957 D. A. AUGUSTIN COMPRESSOR VALVESTRUCTURE 2 SheetsSheet 1 INVENTOR 0A ROLD A. A0606 TIN ATTORNEYS Oct;13, 1959 D. A. AUGUSTIN 2,903,287

COMPRESSOR VALVE STRUCTURE Filed Sept. 4, 1957 V 2 Sheets-Sheet 2INVENTOR F 7 DAROLD A. AUGUgST/N BY e fizz/vie,

ATTORNEYS United States Patent ic COMPRESSOR VALVE STRUCTURE Darold A.Augustin, Elyria, Ohio, assignor to Bendix- Westinghouse Automotive AirBrake Company, Elyria, Ohio, a corporation of Delaware ApplicationSeptember 4, 1957, Serial N 0. 682,005 2 Claims. or. 137-5253) Thisinvention relates to compressors and more particularly to an improvedvalve structure for compressors.

Heretofore compressors of the reciprocating piston type have utilizedresilient valve strips which cooperate with inlet and outlet ports in avalve plate to control the passage of fluid to and from the compressorcylinder. The strips are usually fixed at one end by being squeezedbetween the plate and cylinder block or head and are free at the otherend to be flexed to open and close the ports by pressure differentialson the opposite sides of the valves as fluid is drawn into and pushedout of the cylinder. With the described arrangement it will be apparentthat valve flexing is rapid and continuous and that the maximum strainon the valve strips occurs at the near proximity of their fixed endswhere they are flexed over the edge of the block or head upon movementto open position. Where there is metal-to-metal contact at this point ofmaximum strain, the life of the valve is of relatively short durationdue to the fatigue and stresses resulting from the valves beingcontinuously bent over the unyielding metallic edge of the head orblock.

A principal object of the present invention is to prolong valve life byproviding a valve structure which eliminates the metal-to-metal contactof the valves with the corner of the head or block over which the valveflexes upon movement to open position.

More specifically, it is an object of the present invention to eliminatethe above described metal-to-metal contact of the valves with the heador block by providing a yielding pad between the valves and the head orblock.

It is a further object of the invention to provide a valve structure forcompressors whereby the gaskets fitting between the valve plate and heador block not only perform their normal function as seals but alsoprovide the yielding pad for the engaged end of the valve strip.

Other objects and their attendant advantages will become apparent as thefollowing detailed description is read in conjunction with theaccompanying drawings wherein:

Fig. 1 is a sectional view taken diametrically through the upper end ofa compressor unit and illustrating an inlet valve arranged in accordancewith the present invention;

Fig. 2 is a plan view on a reduced scale taken substantially along theline 22 of Fig. 1;

Fig. 3 is a sectional view similar to Fig. 1 but showing the outletvalve arranged in accordance with the present invention; and

Fig. 4 is a plan view on a reduced scale taken substantially along theline 44 of Fig. 3.

Referring to the drawings, Figs. 1 and 3 illustrate a compressorembodying the valve structure of the invention. The compressor includesa cylinder block having' a cylinder 12 provided therein andreciprocatory piston 14 operating in the cylinder. The upper end of thecylinder 12 is closed by a valve plate 16 and above this is a cylinderhead -18 which is attached to the block by a plurality of bolts 20engaging threaded holes in the block through registering holes in theplate and head as 2,908,287. Patented Oct. 13, 1959 shown in Fig. 1.Upper and lower gaskets 22, 24 are interposed between the valve plateand the head and block.

With reference to Fig. 1 the valve plate is provided with an inlet port26 which may be one of a pair ofside-byside ports as illustrated in Fig.4 which communicate with an inlet chamber 28 in the cylinder head 18.The chamber 28 is isolated from a discharge chamber 30 in head 18 bymeans of a depending wall 31 in the head which sealingly bears on aclosed portion 32 of upper gasket 22 and leading into chamber 28 is aninlet passage 34 which is connected to atmosphere preferably through theusual filter (not shown). As shown in Fig. 3, a discharge port 36 in thevalve plate 16 connects the cylinder 12 with discharge chamber 30 inhead 18 which in turn is connected with a reservoir (not shown) via thedischarge passage 38 illustrated in Figs. 3 and 4. The inlet anddischarge ports 26, 36 are controlled respectively by leaf or strip typeinlet and discharge valves 40, 42 which are clamped at one end in amanner to be fully described herein after with their free ends overlyingrecesses 44, 46 formed on the opposite faces of the valve plate 16. Thecontours of the recesses conform generally to the shape of therespective valves but are oversized as illustrated in Fig. 4 to insurefreedom of movement of the valves without danger of sticking andadjacent the end of each recess there is an annular ridge surroundingthe inlet and discharge ports 26, 36 to provide valve seats 48, 50 onwhich the free ends of the valves 40, 42 seat as shown in Figs. 1, 3,and 4.

With reference to Fig. 1, the port 26 and the free end of valve 40 areso positioned with respect to cylinder 12 that the tip 49 of the valve40 projects slightly beyond the cylinder 12. A recess 52 is formed inthe cylinder memher to accommodate said projecting tip, and the lowerside of this recess constitutes a stop for limiting the downwardmovement of the free end of the valve 40. As illustrated in Fig. 3, theupward movement of the discharge valve 42 is limited by a boss 56integral with the cylinder head 18 and having a profile substantiallyconforming to the curvature of the valve 42 \as it flexes to openposition.

The construction so far described is substantially conventional, and incompressors utilizing a conventional construction it has been customaryto restrain the fixed end of the valves by some means which usuallyinvolves either resiliently or fixedly clamping the valve ends againstthe upper surface of the block or the lower surface of the head with thevalves being restrained on both sides in metal-to-metal contact wherebythey must bend or flex over a metallic corner or edge during theiropening movement. Since this is the point of maximum valve stress, theunyielding metallic corner of the head or block limits the life of thevalve which can be materially increased by providing a yieldable padwhich covers the entire restrained area of the valve between it and themetallic edge over which the valve flexes in its opening movement.

In accordance with the invention, there is provided an economical andeflicacious means for anchoring the restrained end of the valve byutilizing portions of the gaskets 22, 24 which provides the desired padwith substantially no additional cost over the conventional means foranchoring the inner end of valve strips.

Referring first to the inlet valve 40 illustrated in Figs. 1 and 2, itwill be observed that its end 58 is enlarged and suitably apertured toreceive guide pins 60 which extend into the cylinder block. Preferablyone pin-receiving aperture is of slot-like form as indicated at 61 andhas a width suflicient to accommodate its pin 60 so that the valve isrestrained from pivoting laterally about the pins while at the same timethe slots eliminate the necessity of placing the pins in the block so asto .be in exact registry with the apertures which would be. the

case if each aperture were round. Surrounding the guide pins 60 in theblock is a recess 62 having a depth preferably greater than thethickness of the valve 40 for purposes more fully explained hereinafter.The gasket initially is formed flat and is provided with an elongatedtransverse slot 63 which registers with the pins 60 which projectupwardly a sufiicient distance to accommodate the gasket in its flatcondition with the valve 40 thereover prior to assembly of the head andplate to the block. The area of recess 62 is sufficiently large toaccommodate the end 58 of the valve, and the gasket in its flatcondition substantially covers the entire area of the recess. Thegasket, adjacent the free end of the valve, is cut away as shown at 64in Fig. 2, so as not to interfere with the movement of the free end inthe recess 52.

Prior to final assembly of the head, plate, and block the gasket 24 inits flat condition is laid atop the block with the aligning pins 60projecting through the slot 63 in the gasket. The valve 40 is thenassembled over the pins with the end 58 lying atop the gasket. When theplate 16 and head 18 are assembled and bolted in place the lower surfaceof the plate, to the left of the relieved area 44 in Fig. l, forces theend 58 of the valve down onto the gasket causing the portion thereoflying over the recess 62 to be displaced downwardly out of the plane ofthe gasket to substantially fill the recess below the valve end 58. Thedisplaced portion of the gasket is indicated at 66 in Fig. 1 and it willbe observed that this portion 66 provides a pad below the valve whicheliminates over the entire area of the underside of the clamped portionof the valve any metal-to-metal contact of this part with the edge ofthe cylinder block.

Referring to Figs. 3 and 4, the manner of clamping the end of thedischarge valve 42 is substantially the same as that described for theinlet valve with guide pins 68 being provided to register with a slot 69in the gasket and with apertures in the clamped end 7i) of the valve 42.Since the discharge valve 42 flexes upwardly to open position, a recess71 is provided in the head 18 and the initially flat gasket 22 is laidover the valve prior to assembly. When the head is bolted to the block,the end 70 of the valve forces the portion 72 of the gasket into therecess to provide a pad for the valve in its direction of flexure andover its entire clamped area exactly as in the case of the inlet valve40.

It will be apparent to those skilled in the art that with the gasketserving not only as a seal but also as the means for clamping andcushioning the valve ends, the depth of the recesses 62, 71 should beless than the combined thickness of the valve and gasket and thiscombined thickness in turn should be not greater than the depth of therecess plus the thickness of the gasket. Were this not so, there wouldbe the possibility that the valve seated on the depressed portion of thegasket would project sufficiently above the cylinder edge to prevent theplate 16 from being clamped into sealing engagement with the gasketaround the top of the cylinder 10 or around the bottom of the head 18.Expressed another way, sealing engagement of the gasket with the head orblock will be assured provided the valve thickness is not greater thanthe depth of the recess and provided the gasket has a substantiallyuniform thickness over its entire area. Inasmuch as the gasket yields incompression when clamped, the difference between the thickness of thevalve and the depth of the recess is very nearly if not completely takenup by that portion of the gasket registering with the recess so that thevalve end is effectively clamped. It will be apparent from theforegoing, however, that the clamping pressure on the valve will be lessthan the clamping pressure on the sealing portion of the gasket.

From the foregoing description it will be observed that the restrainedends of the valves are satisfactorily anchored without ever being inmetal-to-metal contact with the corner or edge of the head or block overwhich the valves flex to open position. Should the gasket material besheared between the vertical wall of the recess and the inner edge ofthe valve, this will not in any way affect the function of the gasketeither as a seal or as a pad for the restrained end of the valve.Additionally, since the gasket is of an inherently yielding nature, upona tendency of the valves to move towards open position, the pad yieldsinitially to permit some slight movement of the valve bodily towardsopen position before the valve actually flexes. This function alonematerially increases the life of valve over the increase afforded by thesemi-resilient edge provided by the pad over which the valves flex. Byproviding a pad under or over the entire restrained area of therespective valves the free ends thereof seat firmly against their seatsdue to their inherent resiliency reacting against the semi-resilientgasket pad without any tendency of the valve to sag or cock away fromthe seats which might be the case were only a small area of therestrained ends of the valve to be engaged by clamping means or if thevalve were engaged loosely on pins with a dependence on a gasket of theexact thickness of the valve to permit clamping of the valves in placebetween the valve plate and block or head.

It will be apparent that the constructional details of the compressorand of the valves and seats are exemplary only and that these may varywithin Wide limits without, however, departing from the scope and limitsof the appended claims.

What is claimed is:

1. In a compressor comprising a ported valve plate, a cooperating partadapted to receive said valve plate and a gasket of yielding materialproviding a seal between said valve plate and said part, a resilientstrip valve arranged parallel to said plate and having a substantiallyunrestricted free end portion overlying said Yport to close the same.the opposite end portion of said valve being clamped between said valveplate on the ,one side and said gasket on the other, said cooperatingpart being relieved to provide a recessed area at least coextensive withthe clampedportion of said valve and having a depth greater than thethickness of said valve, and said recessed area having means formounting said opposite end portion of the valve against lateral movementwith respect to said cooperating part, the portion of said gasketoverlying said recess being yieldable and forced thereinto by theclamped portion of said valve when said valve plate is moved intosealing engagement with said gasket and said cooperating part.

2. In a compressor a member defining a chamber, a valve plate overlyingthe member, the valve plate being provided with port means therethrough,a resilient strip valve having a restrained end portion and asubstantially unrestricted free end overlying said port to close thesame, a recess in said member to receive the restrained end portion ofsaid valve and having means for preventing lateral movement of saidvalve with respect to said member, a gasket of yielding materialinterposed between said member and said plate and having a portionextending over said recess, said portion of the combined thickness ofthe restrained end portion of said valve and the gasket not exceedingthe depth of said recess plus the thickness of the gasket, said gasketbeing interposed between the restrained end of said valve and saidrecess whereby when said gasket is in sealing relationship with saidvalve plate and said member said restrained end portion of said valvedepresses the overlying portion of said gasket into said recess toprovide a yielding pad between said end portion and said member.

References Cited in the file of this patent UNITED STATES PATENTS2,120,852 Bixler June 14, 1938 2,217,380 Pedder Oct. 8, 1940 2,672,101Shields Mar. 16, 1954

